ASCOSPORE DISPERSAL OF CERATOCYSTIOPSIS-RANACULOSUS, A MYCANGIAL FUNGUS OF THE SOUTHERN PINE-BEETLE

Ascospores of the heterothallic fungus Ceratocystiopsis ranaculosus we re found in sporothecae of three mite species of the genus Tarsonemus. These mites were phoretic on the coniferous bark beetles Dendroctonus frontalis, D. brevicomis, and Ips acuminatus. Ceratocystiopsis ranacu losus inhabits the mycangium of both Dendroctonus species as conidia i n a budding yeast-like form. Ascospores are not known to occur in myca ngia of bark beetles, and the means of ascospore dispersal has not pre viously been reported. It is postulated that ascospores transported by phoretic mites may be responsible for establishing sexually compatibl e colonies of the fungus in beetle galleries either by themselves or i n combination with the mycangial fungus type.